
;(function(){
var UPNG = {};

var pako = require('./pako.min.js');
module.exports = UPNG;
(function(UPNG, pako){

	

	

UPNG.toRGBA8 = function(out)
{
	var w = out.width, h = out.height;
	if(out.tabs.acTL==null) return [UPNG.toRGBA8.decodeImage(out.data, w, h, out).buffer];
	
	var frms = [];
	if(out.frames[0].data==null) out.frames[0].data = out.data;
	
	var img, empty = new Uint8Array(w*h*4);
	for(var i=0; i<out.frames.length; i++)
	{
		var frm = out.frames[i];
		var fx=frm.rect.x, fy=frm.rect.y, fw = frm.rect.width, fh = frm.rect.height;
		var fdata = UPNG.toRGBA8.decodeImage(frm.data, fw,fh, out);
		
		if(i==0) img = fdata;
		else if(frm.blend  ==0) UPNG._copyTile(fdata, fw, fh, img, w, h, fx, fy, 0);
		else if(frm.blend  ==1) UPNG._copyTile(fdata, fw, fh, img, w, h, fx, fy, 1);
		
		frms.push(img.buffer);  img = img.slice(0);
		
		if     (frm.dispose==0) {}
		else if(frm.dispose==1) UPNG._copyTile(empty, fw, fh, img, w, h, fx, fy, 0);
		else if(frm.dispose==2) {
			var pi = i-1;
			while(out.frames[pi].dispose==2) pi--;
			img = new Uint8Array(frms[pi]).slice(0);
		}
	}
	return frms;
}
UPNG.toRGBA8.decodeImage = function(data, w, h, out)
{
	var area = w*h, bpp = UPNG.decode._getBPP(out);
	var bpl = Math.ceil(w*bpp/8);	// bytes per line

	var bf = new Uint8Array(area*4), bf32 = new Uint32Array(bf.buffer);
	var ctype = out.ctype, depth = out.depth;
	var rs = UPNG._bin.readUshort;
	
	//console.log(ctype, depth);

	if     (ctype==6) { // RGB + alpha
		var qarea = area<<2;
		if(depth== 8) for(var i=0; i<qarea;i++) {  bf[i] = data[i];  /*if((i&3)==3 && data[i]!=0) bf[i]=255;*/ }
		if(depth==16) for(var i=0; i<qarea;i++) {  bf[i] = data[i<<1];  }
	}
	else if(ctype==2) {	// RGB
		var ts=out.tabs["tRNS"], tr=-1, tg=-1, tb=-1;
		if(ts) {  tr=ts[0];  tg=ts[1];  tb=ts[2];  }
		if(depth== 8) for(var i=0; i<area; i++) {  var qi=i<<2, ti=i*3;  bf[qi] = data[ti];  bf[qi+1] = data[ti+1];  bf[qi+2] = data[ti+2];  bf[qi+3] = 255;
			if(tr!=-1 && data[ti]   ==tr && data[ti+1]   ==tg && data[ti+2]   ==tb) bf[qi+3] = 0;  }
		if(depth==16) for(var i=0; i<area; i++) {  var qi=i<<2, ti=i*6;  bf[qi] = data[ti];  bf[qi+1] = data[ti+2];  bf[qi+2] = data[ti+4];  bf[qi+3] = 255;
			if(tr!=-1 && rs(data,ti)==tr && rs(data,ti+2)==tg && rs(data,ti+4)==tb) bf[qi+3] = 0;  }
	}
	else if(ctype==3) {	// palette
		var p=out.tabs["PLTE"], ap=out.tabs["tRNS"], tl=ap?ap.length:0;
		//console.log(p, ap);
		if(depth==1) for(var y=0; y<h; y++) {  var s0 = y*bpl, t0 = y*w;
			for(var i=0; i<w; i++) { var qi=(t0+i)<<2, j=((data[s0+(i>>3)]>>(7-((i&7)<<0)))& 1), cj=3*j;  bf[qi]=p[cj];  bf[qi+1]=p[cj+1];  bf[qi+2]=p[cj+2];  bf[qi+3]=(j<tl)?ap[j]:255;  }
		}
		if(depth==2) for(var y=0; y<h; y++) {  var s0 = y*bpl, t0 = y*w;
			for(var i=0; i<w; i++) { var qi=(t0+i)<<2, j=((data[s0+(i>>2)]>>(6-((i&3)<<1)))& 3), cj=3*j;  bf[qi]=p[cj];  bf[qi+1]=p[cj+1];  bf[qi+2]=p[cj+2];  bf[qi+3]=(j<tl)?ap[j]:255;  }
		}
		if(depth==4) for(var y=0; y<h; y++) {  var s0 = y*bpl, t0 = y*w;
			for(var i=0; i<w; i++) { var qi=(t0+i)<<2, j=((data[s0+(i>>1)]>>(4-((i&1)<<2)))&15), cj=3*j;  bf[qi]=p[cj];  bf[qi+1]=p[cj+1];  bf[qi+2]=p[cj+2];  bf[qi+3]=(j<tl)?ap[j]:255;  }
		}
		if(depth==8) for(var i=0; i<area; i++ ) {  var qi=i<<2, j=data[i]                      , cj=3*j;  bf[qi]=p[cj];  bf[qi+1]=p[cj+1];  bf[qi+2]=p[cj+2];  bf[qi+3]=(j<tl)?ap[j]:255;  }
	}
	else if(ctype==4) {	// gray + alpha
		if(depth== 8)  for(var i=0; i<area; i++) {  var qi=i<<2, di=i<<1, gr=data[di];  bf[qi]=gr;  bf[qi+1]=gr;  bf[qi+2]=gr;  bf[qi+3]=data[di+1];  }
		if(depth==16)  for(var i=0; i<area; i++) {  var qi=i<<2, di=i<<2, gr=data[di];  bf[qi]=gr;  bf[qi+1]=gr;  bf[qi+2]=gr;  bf[qi+3]=data[di+2];  }
	}
	else if(ctype==0) {	// gray
		var tr = out.tabs["tRNS"] ? out.tabs["tRNS"] : -1;
		if(depth== 1) for(var i=0; i<area; i++) {  var gr=255*((data[i>>3]>>(7 -((i&7)   )))& 1), al=(gr==tr*255)?0:255;  bf32[i]=(al<<24)|(gr<<16)|(gr<<8)|gr;  }
		if(depth== 2) for(var i=0; i<area; i++) {  var gr= 85*((data[i>>2]>>(6 -((i&3)<<1)))& 3), al=(gr==tr* 85)?0:255;  bf32[i]=(al<<24)|(gr<<16)|(gr<<8)|gr;  }
		if(depth== 4) for(var i=0; i<area; i++) {  var gr= 17*((data[i>>1]>>(4 -((i&1)<<2)))&15), al=(gr==tr* 17)?0:255;  bf32[i]=(al<<24)|(gr<<16)|(gr<<8)|gr;  }
		if(depth== 8) for(var i=0; i<area; i++) {  var gr=data[i  ] , al=(gr           ==tr)?0:255;  bf32[i]=(al<<24)|(gr<<16)|(gr<<8)|gr;  }
		if(depth==16) for(var i=0; i<area; i++) {  var gr=data[i<<1], al=(rs(data,i<<1)==tr)?0:255;  bf32[i]=(al<<24)|(gr<<16)|(gr<<8)|gr;  }
	}
	return bf;
}



UPNG.decode = function(buff)
{
	var data = new Uint8Array(buff), offset = 8, bin = UPNG._bin, rUs = bin.readUshort, rUi = bin.readUint;
	var out = {tabs:{}, frames:[]};
	var dd = new Uint8Array(data.length), doff = 0;	 // put all IDAT data into it
	var fd, foff = 0;	// frames
	
	var mgck = [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a];
	for(var i=0; i<8; i++) if(data[i]!=mgck[i]) throw "The input is not a PNG file!";

	while(offset<data.length)
	{
		var len  = bin.readUint(data, offset);  offset += 4;
		var type = bin.readASCII(data, offset, 4);  offset += 4;
		//log(type,len);
		
		if     (type=="IHDR")  {  UPNG.decode._IHDR(data, offset, out);  }
		else if(type=="IDAT") {
			for(var i=0; i<len; i++) dd[doff+i] = data[offset+i];
			doff += len;
		}
		else if(type=="acTL")  {
			out.tabs[type] = {  num_frames:rUi(data, offset), num_plays:rUi(data, offset+4)  };
			fd = new Uint8Array(data.length);
		}
		else if(type=="fcTL")  {
			if(foff!=0) {  var fr = out.frames[out.frames.length-1];
				fr.data = UPNG.decode._decompress(out, fd.slice(0,foff), fr.rect.width, fr.rect.height);  foff=0;
			}
			var rct = {x:rUi(data, offset+12),y:rUi(data, offset+16),width:rUi(data, offset+4),height:rUi(data, offset+8)};
			var del = rUs(data, offset+22);  del = rUs(data, offset+20) / (del==0?100:del);
			var frm = {rect:rct, delay:Math.round(del*1000), dispose:data[offset+24], blend:data[offset+25]};
			//console.log(frm);
			out.frames.push(frm);
		}
		else if(type=="fdAT") {
			for(var i=0; i<len-4; i++) fd[foff+i] = data[offset+i+4];
			foff += len-4;
		}
		else if(type=="pHYs") {
			out.tabs[type] = [bin.readUint(data, offset), bin.readUint(data, offset+4), data[offset+8]];
		}
		else if(type=="cHRM") {
			out.tabs[type] = [];
			for(var i=0; i<8; i++) out.tabs[type].push(bin.readUint(data, offset+i*4));
		}
		else if(type=="tEXt") {
			if(out.tabs[type]==null) out.tabs[type] = {};
			var nz = bin.nextZero(data, offset);
			var keyw = bin.readASCII(data, offset, nz-offset);
			var text = bin.readASCII(data, nz+1, offset+len-nz-1);
			out.tabs[type][keyw] = text;
		}
		else if(type=="iTXt") {
			if(out.tabs[type]==null) out.tabs[type] = {};
			var nz = 0, off = offset;
			nz = bin.nextZero(data, off);
			var keyw = bin.readASCII(data, off, nz-off);  off = nz + 1;
			var cflag = data[off], cmeth = data[off+1];  off+=2;
			nz = bin.nextZero(data, off);
			var ltag = bin.readASCII(data, off, nz-off);  off = nz + 1;
			nz = bin.nextZero(data, off);
			var tkeyw = bin.readUTF8(data, off, nz-off);  off = nz + 1;
			var text  = bin.readUTF8(data, off, len-(off-offset));
			out.tabs[type][keyw] = text;
		}
		else if(type=="PLTE") {
			out.tabs[type] = bin.readBytes(data, offset, len);
		}
		else if(type=="hIST") {
			var pl = out.tabs["PLTE"].length/3;
			out.tabs[type] = [];  for(var i=0; i<pl; i++) out.tabs[type].push(rUs(data, offset+i*2));
		}
		else if(type=="tRNS") {
			if     (out.ctype==3) out.tabs[type] = bin.readBytes(data, offset, len);
			else if(out.ctype==0) out.tabs[type] = rUs(data, offset);
			else if(out.ctype==2) out.tabs[type] = [ rUs(data,offset),rUs(data,offset+2),rUs(data,offset+4) ];
			//else console.log("tRNS for unsupported color type",out.ctype, len);
		}
		else if(type=="gAMA") out.tabs[type] = bin.readUint(data, offset)/100000;
		else if(type=="sRGB") out.tabs[type] = data[offset];
		else if(type=="bKGD")
		{
			if     (out.ctype==0 || out.ctype==4) out.tabs[type] = [rUs(data, offset)];
			else if(out.ctype==2 || out.ctype==6) out.tabs[type] = [rUs(data, offset), rUs(data, offset+2), rUs(data, offset+4)];
			else if(out.ctype==3) out.tabs[type] = data[offset];
		}
		else if(type=="IEND") {
			if(foff!=0) {  var fr = out.frames[out.frames.length-1];
				fr.data = UPNG.decode._decompress(out, fd.slice(0,foff), fr.rect.width, fr.rect.height);  foff=0;
			}	
			out.data = UPNG.decode._decompress(out, dd, out.width, out.height);  break;
		}
		//else {  log("unknown chunk type", type, len);  }
		offset += len;
		var crc = bin.readUint(data, offset);  offset += 4;
	}
	delete out.compress;  delete out.interlace;  delete out.filter;
	return out;
}

UPNG.decode._decompress = function(out, dd, w, h) {
	if(out.compress ==0) dd = UPNG.decode._inflate(dd);

	if     (out.interlace==0) dd = UPNG.decode._filterZero(dd, out, 0, w, h);
	else if(out.interlace==1) dd = UPNG.decode._readInterlace(dd, out);
	return dd;
}

UPNG.decode._inflate = function(data) {  return pako["inflate"](data);  }

UPNG.decode._readInterlace = function(data, out)
{
	var w = out.width, h = out.height;
	var bpp = UPNG.decode._getBPP(out), cbpp = bpp>>3, bpl = Math.ceil(w*bpp/8);
	var img = new Uint8Array( h * bpl );
	var di = 0;

	var starting_row  = [ 0, 0, 4, 0, 2, 0, 1 ];
	var starting_col  = [ 0, 4, 0, 2, 0, 1, 0 ];
	var row_increment = [ 8, 8, 8, 4, 4, 2, 2 ];
	var col_increment = [ 8, 8, 4, 4, 2, 2, 1 ];

	var pass=0;
	while(pass<7)
	{
		var ri = row_increment[pass], ci = col_increment[pass];
		var sw = 0, sh = 0;
		var cr = starting_row[pass];  while(cr<h) {  cr+=ri;  sh++;  }
		var cc = starting_col[pass];  while(cc<w) {  cc+=ci;  sw++;  }
		var bpll = Math.ceil(sw*bpp/8);
		UPNG.decode._filterZero(data, out, di, sw, sh);

		var y=0, row = starting_row[pass];
		while(row<h)
		{
			var col = starting_col[pass];
			var cdi = (di+y*bpll)<<3;

			while(col<w)
			{
				if(bpp==1) {
					var val = data[cdi>>3];  val = (val>>(7-(cdi&7)))&1;
					img[row*bpl + (col>>3)] |= (val << (7-((col&3)<<0)));
				}
				if(bpp==2) {
					var val = data[cdi>>3];  val = (val>>(6-(cdi&7)))&3;
					img[row*bpl + (col>>2)] |= (val << (6-((col&3)<<1)));
				}
				if(bpp==4) {
					var val = data[cdi>>3];  val = (val>>(4-(cdi&7)))&15;
					img[row*bpl + (col>>1)] |= (val << (4-((col&1)<<2)));
				}
				if(bpp>=8) {
					var ii = row*bpl+col*cbpp;
					for(var j=0; j<cbpp; j++) img[ii+j] = data[(cdi>>3)+j];
				}
				cdi+=bpp;  col+=ci;
			}
			y++;  row += ri;
		}
		if(sw*sh!=0) di += sh * (1 + bpll);
		pass = pass + 1;
	}
	return img;
}

UPNG.decode._getBPP = function(out) {
	var noc = [1,null,3,1,2,null,4][out.ctype];
	return noc * out.depth;
}

UPNG.decode._filterZero = function(data, out, off, w, h)
{
	var bpp = UPNG.decode._getBPP(out), bpl = Math.ceil(w*bpp/8), paeth = UPNG.decode._paeth;
	bpp = Math.ceil(bpp/8);

	for(var y=0; y<h; y++)  {
		var i = off+y*bpl, di = i+y+1;
		var type = data[di-1];

		if     (type==0) for(var x=  0; x<bpl; x++) data[i+x] = data[di+x];
		else if(type==1) {
			for(var x=  0; x<bpp; x++) data[i+x] = data[di+x];
			for(var x=bpp; x<bpl; x++) data[i+x] = (data[di+x] + data[i+x-bpp])&255;
		}
		else if(y==0) {
			for(var x=  0; x<bpp; x++) data[i+x] = data[di+x];
			if(type==2) for(var x=bpp; x<bpl; x++) data[i+x] = (data[di+x])&255;
			if(type==3) for(var x=bpp; x<bpl; x++) data[i+x] = (data[di+x] + (data[i+x-bpp]>>1) )&255;
			if(type==4) for(var x=bpp; x<bpl; x++) data[i+x] = (data[di+x] + paeth(data[i+x-bpp], 0, 0) )&255;
		}
		else {
			if(type==2) { for(var x=  0; x<bpl; x++) data[i+x] = (data[di+x] + data[i+x-bpl])&255;  }

			if(type==3) { for(var x=  0; x<bpp; x++) data[i+x] = (data[di+x] + (data[i+x-bpl]>>1))&255;
			              for(var x=bpp; x<bpl; x++) data[i+x] = (data[di+x] + ((data[i+x-bpl]+data[i+x-bpp])>>1) )&255;  }

			if(type==4) { for(var x=  0; x<bpp; x++) data[i+x] = (data[di+x] + paeth(0, data[i+x-bpl], 0))&255;
						  for(var x=bpp; x<bpl; x++) data[i+x] = (data[di+x] + paeth(data[i+x-bpp], data[i+x-bpl], data[i+x-bpp-bpl]) )&255;  }
		}
	}
	return data;
}

UPNG.decode._paeth = function(a,b,c)
{
	var p = a+b-c, pa = Math.abs(p-a), pb = Math.abs(p-b), pc = Math.abs(p-c);
	if (pa <= pb && pa <= pc)  return a;
	else if (pb <= pc)  return b;
	return c;
}

UPNG.decode._IHDR = function(data, offset, out)
{
	var bin = UPNG._bin;
	out.width  = bin.readUint(data, offset);  offset += 4;
	out.height = bin.readUint(data, offset);  offset += 4;
	out.depth     = data[offset];  offset++;
	out.ctype     = data[offset];  offset++;
	out.compress  = data[offset];  offset++;
	out.filter    = data[offset];  offset++;
	out.interlace = data[offset];  offset++;
}

UPNG._bin = {
	nextZero   : function(data,p)  {  while(data[p]!=0) p++;  return p;  },
	readUshort : function(buff,p)  {  return (buff[p]<< 8) | buff[p+1];  },
	writeUshort: function(buff,p,n){  buff[p] = (n>>8)&255;  buff[p+1] = n&255;  },
	readUint   : function(buff,p)  {  return (buff[p]*(256*256*256)) + ((buff[p+1]<<16) | (buff[p+2]<< 8) | buff[p+3]);  },
	writeUint  : function(buff,p,n){  buff[p]=(n>>24)&255;  buff[p+1]=(n>>16)&255;  buff[p+2]=(n>>8)&255;  buff[p+3]=n&255;  },
	readASCII  : function(buff,p,l){  var s = "";  for(var i=0; i<l; i++) s += String.fromCharCode(buff[p+i]);  return s;    },
	writeASCII : function(data,p,s){  for(var i=0; i<s.length; i++) data[p+i] = s.charCodeAt(i);  },
	readBytes  : function(buff,p,l){  var arr = [];   for(var i=0; i<l; i++) arr.push(buff[p+i]);   return arr;  },
	pad : function(n) { return n.length < 2 ? "0" + n : n; },
	readUTF8 : function(buff, p, l) {
		var s = "", ns;
		for(var i=0; i<l; i++) s += "%" + UPNG._bin.pad(buff[p+i].toString(16));
		try {  ns = decodeURIComponent(s); }
		catch(e) {  return UPNG._bin.readASCII(buff, p, l);  }
		return  ns;
	}
}
UPNG._copyTile = function(sb, sw, sh, tb, tw, th, xoff, yoff, mode)
{
	var w = Math.min(sw,tw), h = Math.min(sh,th);
	var si=0, ti=0;
	for(var y=0; y<h; y++)
		for(var x=0; x<w; x++)
		{
			if(xoff>=0 && yoff>=0) {  si = (y*sw+x)<<2;  ti = (( yoff+y)*tw+xoff+x)<<2;  }
			else                   {  si = ((-yoff+y)*sw-xoff+x)<<2;  ti = (y*tw+x)<<2;  }
			
			if     (mode==0) {  tb[ti] = sb[si];  tb[ti+1] = sb[si+1];  tb[ti+2] = sb[si+2];  tb[ti+3] = sb[si+3];  }
			else if(mode==1) {
				var fa = sb[si+3]*(1/255), fr=sb[si]*fa, fg=sb[si+1]*fa, fb=sb[si+2]*fa; 
				var ba = tb[ti+3]*(1/255), br=tb[ti]*ba, bg=tb[ti+1]*ba, bb=tb[ti+2]*ba; 
				
				var ifa=1-fa, oa = fa+ba*ifa, ioa = (oa==0?0:1/oa);
				tb[ti+3] = 255*oa;  
				tb[ti+0] = (fr+br*ifa)*ioa;  
				tb[ti+1] = (fg+bg*ifa)*ioa;   
				tb[ti+2] = (fb+bb*ifa)*ioa;  
			}
			else if(mode==2){	// copy only differences, otherwise zero
				var fa = sb[si+3], fr=sb[si], fg=sb[si+1], fb=sb[si+2]; 
				var ba = tb[ti+3], br=tb[ti], bg=tb[ti+1], bb=tb[ti+2]; 
				if(fa==ba && fr==br && fg==bg && fb==bb) {  tb[ti]=0;  tb[ti+1]=0;  tb[ti+2]=0;  tb[ti+3]=0;  }
				else {  tb[ti]=fr;  tb[ti+1]=fg;  tb[ti+2]=fb;  tb[ti+3]=fa;  }
			}
			else if(mode==3){	// check if can be blended
				var fa = sb[si+3], fr=sb[si], fg=sb[si+1], fb=sb[si+2]; 
				var ba = tb[ti+3], br=tb[ti], bg=tb[ti+1], bb=tb[ti+2]; 
				if(fa==ba && fr==br && fg==bg && fb==bb) continue;
				//if(fa!=255 && ba!=0) return false;
				if(fa<220 && ba>20) return false;
			}
		}
	return true;
}



UPNG.encode = function(bufs, w, h, ps, dels, forbidPlte)
{
	if(ps==null) ps=0;
	if(forbidPlte==null) forbidPlte = false;
	var data = new Uint8Array(bufs[0].byteLength*bufs.length+100);
	var wr=[0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a];
	for(var i=0; i<8; i++) data[i]=wr[i];
	var offset = 8,  bin = UPNG._bin, crc = UPNG.crc.crc, wUi = bin.writeUint, wUs = bin.writeUshort, wAs = bin.writeASCII;

	var nimg = UPNG.encode.compressPNG(bufs, w, h, ps, forbidPlte);

	wUi(data,offset, 13);     offset+=4;
	wAs(data,offset,"IHDR");  offset+=4;
	wUi(data,offset,w);  offset+=4;
	wUi(data,offset,h);  offset+=4;
	data[offset] = nimg.depth;  offset++;  // depth
	data[offset] = nimg.ctype;  offset++;  // ctype
	data[offset] = 0;  offset++;  // compress
	data[offset] = 0;  offset++;  // filter
	data[offset] = 0;  offset++;  // interlace
	wUi(data,offset,crc(data,offset-17,17));  offset+=4; // crc

	// 9 bytes to say, that it is sRGB
	wUi(data,offset, 1);      offset+=4;
	wAs(data,offset,"sRGB");  offset+=4;
	data[offset] = 1;  offset++;
	wUi(data,offset,crc(data,offset-5,5));  offset+=4; // crc

	var anim = bufs.length>1;
	if(anim) {
		wUi(data,offset, 8);      offset+=4;
		wAs(data,offset,"acTL");  offset+=4;
		wUi(data,offset, bufs.length);      offset+=4;
		wUi(data,offset, 0);      offset+=4;
		wUi(data,offset,crc(data,offset-12,12));  offset+=4; // crc
	}

	if(nimg.ctype==3) {
		var dl = nimg.plte.length;
		wUi(data,offset, dl*3);  offset+=4;
		wAs(data,offset,"PLTE");  offset+=4;
		for(var i=0; i<dl; i++){
			var ti=i*3, c=nimg.plte[i], r=(c)&255, g=(c>>8)&255, b=(c>>16)&255;
			data[offset+ti+0]=r;  data[offset+ti+1]=g;  data[offset+ti+2]=b;
		}
		offset+=dl*3;
		wUi(data,offset,crc(data,offset-dl*3-4,dl*3+4));  offset+=4; // crc

		if(nimg.gotAlpha) {
			wUi(data,offset, dl);  offset+=4;
			wAs(data,offset,"tRNS");  offset+=4;
			for(var i=0; i<dl; i++)  data[offset+i]=(nimg.plte[i]>>24)&255;
			offset+=dl;
			wUi(data,offset,crc(data,offset-dl-4,dl+4));  offset+=4; // crc
		}
	}
	
	var fi = 0;
	for(var j=0; j<nimg.frames.length; j++)
	{
		var fr = nimg.frames[j];
		if(anim) {
			wUi(data,offset, 26);     offset+=4;
			wAs(data,offset,"fcTL");  offset+=4;
			wUi(data, offset, fi++);   offset+=4;
			wUi(data, offset, fr.rect.width );   offset+=4;
			wUi(data, offset, fr.rect.height);   offset+=4;
			wUi(data, offset, fr.rect.x);   offset+=4;
			wUi(data, offset, fr.rect.y);   offset+=4;
			wUs(data, offset, dels[j]);   offset+=2;
			wUs(data, offset,  1000);   offset+=2;
			data[offset] = fr.dispose;  offset++;	// dispose
			data[offset] = fr.blend  ;  offset++;	// blend
			wUi(data,offset,crc(data,offset-30,30));  offset+=4; // crc
		}
				
		var imgd = fr.cimg, dl = imgd.length;
		wUi(data,offset, dl+(j==0?0:4));     offset+=4;
		var ioff = offset;
		wAs(data,offset,(j==0)?"IDAT":"fdAT");  offset+=4;
		if(j!=0) {  wUi(data, offset, fi++);  offset+=4;  }
		for(var i=0; i<dl; i++) data[offset+i] = imgd[i];
		offset += dl;
		wUi(data,offset,crc(data,ioff,offset-ioff));  offset+=4; // crc
	}

	wUi(data,offset, 0);     offset+=4;
	wAs(data,offset,"IEND");  offset+=4;
	wUi(data,offset,crc(data,offset-4,4));  offset+=4; // crc

	return data.buffer.slice(0,offset);
}

UPNG.encode.compressPNG = function(bufs, w, h, ps, forbidPlte)
{
	var out = UPNG.encode.compress(bufs, w, h, ps, false, forbidPlte);
	for(var i=0; i<bufs.length; i++) {
		var frm = out.frames[i], nw=frm.rect.width, nh=frm.rect.height, bpl=frm.bpl, bpp=frm.bpp;
		var fdata = new Uint8Array(nh*bpl+nh);
		frm.cimg = UPNG.encode._filterZero(frm.img,nh,bpp,bpl,fdata);
	}	
	return out;
}

UPNG.encode.compress = function(bufs, w, h, ps, forGIF, forbidPlte)
{
	if(forbidPlte==null) forbidPlte = false;
	
	var ctype = 6, depth = 8, bpp = 4, alphaAnd=255
	
	for(var j=0; j<bufs.length; j++)  {  // when not quantized, other frames can contain colors, that are not in an initial frame
		var img = new Uint8Array(bufs[j]), ilen = img.length;
		for(var i=0; i<ilen; i+=4) alphaAnd &= img[i+3];
	}
	var gotAlpha = (alphaAnd)!=255;
	
	var cmap={}, plte=[];  if(bufs.length!=0) {  cmap[0]=0;  plte.push(0);  if(ps!=0) ps--;  } 
	
	
	if(ps!=0) {
		var qres = UPNG.quantize(bufs, ps, forGIF);  bufs = qres.bufs;
		for(var i=0; i<qres.plte.length; i++) {  var c=qres.plte[i].est.rgba;  if(cmap[c]==null) {  cmap[c]=plte.length;  plte.push(c);  }     }
	}
	else {
		// what if ps==0, but there are <=256 colors?  we still need to detect, if the palette could be used
		for(var j=0; j<bufs.length; j++)  {  // when not quantized, other frames can contain colors, that are not in an initial frame
			var img32 = new Uint32Array(bufs[j]), ilen = img32.length;
			for(var i=0; i<ilen; i++) {
				var c = img32[i];
				if((i<w || (c!=img32[i-1] && c!=img32[i-w])) && cmap[c]==null) {  cmap[c]=plte.length;  plte.push(c);  if(plte.length>=300) break;  }
			}
		}
	}
	
	var brute = gotAlpha ? forGIF : false;		// brute : frames can only be copied, not "blended"
	var cc=plte.length;  //console.log(cc);
	if(cc<=256 && forbidPlte==false) {
		if(cc<= 2) depth=1;  else if(cc<= 4) depth=2;  else if(cc<=16) depth=4;  else depth=8;
		if(forGIF) depth=8;
		gotAlpha = true;
	}
	
	
	var frms = [];
	for(var j=0; j<bufs.length; j++)
	{
		var cimg = new Uint8Array(bufs[j]), cimg32 = new Uint32Array(cimg.buffer);
		
		var nx=0, ny=0, nw=w, nh=h, blend=0;
		if(j!=0 && !brute) {
			var tlim = (forGIF || j==1 || frms[frms.length-2].dispose==2)?1:2, tstp = 0, tarea = 1e9;
			for(var it=0; it<tlim; it++)
			{
				var pimg = new Uint8Array(bufs[j-1-it]), p32 = new Uint32Array(bufs[j-1-it]);
				var mix=w,miy=h,max=-1,may=-1;
				for(var y=0; y<h; y++) for(var x=0; x<w; x++) {
					var i = y*w+x;
					if(cimg32[i]!=p32[i]) {
						if(x<mix) mix=x;  if(x>max) max=x;
						if(y<miy) miy=y;  if(y>may) may=y;
					}
				}
				var sarea = (max==-1) ? 1 : (max-mix+1)*(may-miy+1);
				if(sarea<tarea) {
					tarea = sarea;  tstp = it;  
					if(max==-1) {  nx=ny=0;  nw=nh=1;  }
					else {  nx = mix; ny = miy; nw = max-mix+1; nh = may-miy+1;  }
				}
			}
			
			var pimg = new Uint8Array(bufs[j-1-tstp]);
			if(tstp==1) frms[frms.length-1].dispose = 2;
			
			var nimg = new Uint8Array(nw*nh*4), nimg32 = new Uint32Array(nimg.buffer);
			UPNG.   _copyTile(pimg,w,h, nimg,nw,nh, -nx,-ny, 0);
			if(UPNG._copyTile(cimg,w,h, nimg,nw,nh, -nx,-ny, 3)) {
				UPNG._copyTile(cimg,w,h, nimg,nw,nh, -nx,-ny, 2);  blend = 1;
			}
			else {
				UPNG._copyTile(cimg,w,h, nimg,nw,nh, -nx,-ny, 0);  blend = 0;
			}
			cimg = nimg;  cimg32 = new Uint32Array(cimg.buffer);
		}
		var bpl = 4*nw;
		if(cc<=256 && forbidPlte==false) {
			bpl = Math.ceil(depth*nw/8);
			var nimg = new Uint8Array(bpl*nh);
			for(var y=0; y<nh; y++) {  var i=y*bpl, ii=y*nw;
				if     (depth==8) for(var x=0; x<nw; x++) nimg[i+(x)   ]   =  (cmap[cimg32[ii+x]]             );
				else if(depth==4) for(var x=0; x<nw; x++) nimg[i+(x>>1)]  |=  (cmap[cimg32[ii+x]]<<(4-(x&1)*4));
				else if(depth==2) for(var x=0; x<nw; x++) nimg[i+(x>>2)]  |=  (cmap[cimg32[ii+x]]<<(6-(x&3)*2));
				else if(depth==1) for(var x=0; x<nw; x++) nimg[i+(x>>3)]  |=  (cmap[cimg32[ii+x]]<<(7-(x&7)*1));
			}
			cimg=nimg;  ctype=3;  bpp=1;
		}
		else if(gotAlpha==false && bufs.length==1) {	// some next "reduced" frames may contain alpha for blending
			var nimg = new Uint8Array(nw*nh*3), area=nw*nh;
			for(var i=0; i<area; i++) { var ti=i*3, qi=i*4;  nimg[ti]=cimg[qi];  nimg[ti+1]=cimg[qi+1];  nimg[ti+2]=cimg[qi+2];  }
			cimg=nimg;  ctype=2;  bpp=3;  bpl=3*nw;
		}
		frms.push({rect:{x:nx,y:ny,width:nw,height:nh}, img:cimg, bpl:bpl, bpp:bpp, blend:blend, dispose:brute?1:0});
	}
	return {ctype:ctype, depth:depth, plte:plte, gotAlpha:gotAlpha, frames:frms  };
}

UPNG.encode._filterZero = function(img,h,bpp,bpl,data)
{
	var fls = [];
	for(var t=0; t<5; t++) {  if(h*bpl>500000 && (t==2 || t==3 || t==4)) continue;
		for(var y=0; y<h; y++) UPNG.encode._filterLine(data, img, y, bpl, bpp, t);
		fls.push(pako["deflate"](data));  if(bpp==1) break;
	}
	var ti, tsize=1e9;
	for(var i=0; i<fls.length; i++) if(fls[i].length<tsize) {  ti=i;  tsize=fls[i].length;  }
	return fls[ti];
}
UPNG.encode._filterLine = function(data, img, y, bpl, bpp, type)
{
	var i = y*bpl, di = i+y, paeth = UPNG.decode._paeth
	data[di]=type;  di++;

	if(type==0) for(var x=0; x<bpl; x++) data[di+x] = img[i+x];
	else if(type==1) {
		for(var x=  0; x<bpp; x++) data[di+x] =  img[i+x];
		for(var x=bpp; x<bpl; x++) data[di+x] = (img[i+x]-img[i+x-bpp]+256)&255;
	}
	else if(y==0) {
		for(var x=  0; x<bpp; x++) data[di+x] = img[i+x];

		if(type==2) for(var x=bpp; x<bpl; x++) data[di+x] = img[i+x];
		if(type==3) for(var x=bpp; x<bpl; x++) data[di+x] = (img[i+x] - (img[i+x-bpp]>>1) +256)&255;
		if(type==4) for(var x=bpp; x<bpl; x++) data[di+x] = (img[i+x] - paeth(img[i+x-bpp], 0, 0) +256)&255;
	}
	else {
		if(type==2) { for(var x=  0; x<bpl; x++) data[di+x] = (img[i+x]+256 - img[i+x-bpl])&255;  }
		if(type==3) { for(var x=  0; x<bpp; x++) data[di+x] = (img[i+x]+256 - (img[i+x-bpl]>>1))&255;
					  for(var x=bpp; x<bpl; x++) data[di+x] = (img[i+x]+256 - ((img[i+x-bpl]+img[i+x-bpp])>>1))&255;  }
		if(type==4) { for(var x=  0; x<bpp; x++) data[di+x] = (img[i+x]+256 - paeth(0, img[i+x-bpl], 0))&255;
					  for(var x=bpp; x<bpl; x++) data[di+x] = (img[i+x]+256 - paeth(img[i+x-bpp], img[i+x-bpl], img[i+x-bpp-bpl]))&255;  }
	}
}

UPNG.crc = {
	table : ( function() {
	   var tab = new Uint32Array(256);
	   for (var n=0; n<256; n++) {
			var c = n;
			for (var k=0; k<8; k++) {
				if (c & 1)  c = 0xedb88320 ^ (c >>> 1);
				else        c = c >>> 1;
			}
			tab[n] = c;  }
		return tab;  })(),
	update : function(c, buf, off, len) {
		for (var i=0; i<len; i++)  c = UPNG.crc.table[(c ^ buf[off+i]) & 0xff] ^ (c >>> 8);
		return c;
	},
	crc : function(b,o,l)  {  return UPNG.crc.update(0xffffffff,b,o,l) ^ 0xffffffff;  }
}


UPNG.quantize = function(bufs, ps, roundAlpha)
{	
	var imgs = [], totl = 0;
	for(var i=0; i<bufs.length; i++) {  imgs.push(UPNG.encode.alphaMul(new Uint8Array(bufs[i]), roundAlpha));  totl+=bufs[i].byteLength;  }
	
	var nimg = new Uint8Array(totl), nimg32 = new Uint32Array(nimg.buffer), noff=0;
	for(var i=0; i<imgs.length; i++) {
		var img = imgs[i], il = img.length;
		for(var j=0; j<il; j++) nimg[noff+j] = img[j];
		noff += il;
	}
	
	var root = {i0:0, i1:nimg.length, bst:null, est:null, tdst:0, left:null, right:null };  // basic statistic, extra statistic
	root.bst = UPNG.quantize.stats(  nimg,root.i0, root.i1  );  root.est = UPNG.quantize.estats( root.bst );
	var leafs = [root];
	
	while(leafs.length<ps)
	{
		var maxL = 0, mi=0;
		for(var i=0; i<leafs.length; i++) if(leafs[i].est.L > maxL) {  maxL=leafs[i].est.L;  mi=i;  }
		if(maxL<1e-3) break;
		var node = leafs[mi];
		
		var s0 = UPNG.quantize.splitPixels(nimg,nimg32, node.i0, node.i1, node.est.e, node.est.eMq255);
		
		var ln = {i0:node.i0, i1:s0, bst:null, est:null, tdst:0, left:null, right:null };  ln.bst = UPNG.quantize.stats( nimg, ln.i0, ln.i1 );  
		ln.est = UPNG.quantize.estats( ln.bst );
		var rn = {i0:s0, i1:node.i1, bst:null, est:null, tdst:0, left:null, right:null };  rn.bst = {R:[], m:[], N:node.bst.N-ln.bst.N};
		for(var i=0; i<16; i++) rn.bst.R[i] = node.bst.R[i]-ln.bst.R[i];
		for(var i=0; i< 4; i++) rn.bst.m[i] = node.bst.m[i]-ln.bst.m[i];
		rn.est = UPNG.quantize.estats( rn.bst );
		
		node.left = ln;  node.right = rn;
		leafs[mi]=ln;  leafs.push(rn);
	}
	leafs.sort(function(a,b) {  return b.bst.N-a.bst.N;  });
	
	for(var ii=0; ii<imgs.length; ii++) {
		var planeDst = UPNG.quantize.planeDst;
		var sb = new Uint8Array(imgs[ii].buffer), tb = new Uint32Array(imgs[ii].buffer), len = sb.length;
		
		var stack = [], si=0;
		for(var i=0; i<len; i+=4) {
			var r=sb[i]*(1/255), g=sb[i+1]*(1/255), b=sb[i+2]*(1/255), a=sb[i+3]*(1/255);
			
			//  exact, but too slow :(
			//var nd = UPNG.quantize.getNearest(root, r, g, b, a);
			var nd = root;
			while(nd.left) nd = (planeDst(nd.est,r,g,b,a)<=0) ? nd.left : nd.right;
			
			tb[i>>2] = nd.est.rgba;
		}
		imgs[ii]=tb.buffer;
	}
	return {  bufs:imgs, plte:leafs  };
}
UPNG.quantize.getNearest = function(nd, r,g,b,a)
{
	if(nd.left==null) {  nd.tdst = UPNG.quantize.dist(nd.est.q,r,g,b,a);  return nd;  }
	var planeDst = UPNG.quantize.planeDst(nd.est,r,g,b,a);
	
	var node0 = nd.left, node1 = nd.right;
	if(planeDst>0) {  node0=nd.right;  node1=nd.left;  }
	
	var ln = UPNG.quantize.getNearest(node0, r,g,b,a);
	if(ln.tdst<=planeDst*planeDst) return ln;
	var rn = UPNG.quantize.getNearest(node1, r,g,b,a);
	return rn.tdst<ln.tdst ? rn : ln;
}
UPNG.quantize.planeDst = function(est, r,g,b,a) {  var e = est.e;  return e[0]*r + e[1]*g + e[2]*b + e[3]*a - est.eMq;  }
UPNG.quantize.dist     = function(q,   r,g,b,a) {  var d0=r-q[0], d1=g-q[1], d2=b-q[2], d3=a-q[3];  return d0*d0+d1*d1+d2*d2+d3*d3;  }

UPNG.quantize.splitPixels = function(nimg, nimg32, i0, i1, e, eMq)
{
	var vecDot = UPNG.quantize.vecDot;
	i1-=4;
	var shfs = 0;
	while(i0<i1)
	{
		while(vecDot(nimg, i0, e)<=eMq) i0+=4;
		while(vecDot(nimg, i1, e)> eMq) i1-=4;
		if(i0>=i1) break;
		
		var t = nimg32[i0>>2];  nimg32[i0>>2] = nimg32[i1>>2];  nimg32[i1>>2]=t;
		
		i0+=4;  i1-=4;
	}
	while(vecDot(nimg, i0, e)>eMq) i0-=4;
	return i0+4;
}
UPNG.quantize.vecDot = function(nimg, i, e)
{
	return nimg[i]*e[0] + nimg[i+1]*e[1] + nimg[i+2]*e[2] + nimg[i+3]*e[3];
}
UPNG.quantize.stats = function(nimg, i0, i1){
	var R = [0,0,0,0,  0,0,0,0,  0,0,0,0,  0,0,0,0];
	var m = [0,0,0,0];
	var N = (i1-i0)>>2;
	for(var i=i0; i<i1; i+=4)
	{
		var r = nimg[i]*(1/255), g = nimg[i+1]*(1/255), b = nimg[i+2]*(1/255), a = nimg[i+3]*(1/255);
		//var r = nimg[i], g = nimg[i+1], b = nimg[i+2], a = nimg[i+3];
		m[0]+=r;  m[1]+=g;  m[2]+=b;  m[3]+=a;
		
		R[ 0] += r*r;  R[ 1] += r*g;  R[ 2] += r*b;  R[ 3] += r*a;  
		               R[ 5] += g*g;  R[ 6] += g*b;  R[ 7] += g*a; 
		                              R[10] += b*b;  R[11] += b*a;  
		                                             R[15] += a*a;  
	}
	R[4]=R[1];  R[8]=R[2];  R[12]=R[3];  R[9]=R[6];  R[13]=R[7];  R[14]=R[11];
	
	return {R:R, m:m, N:N};
}
UPNG.quantize.estats = function(stats){
	var R = stats.R, m = stats.m, N = stats.N;
	
	var m0 = m[0], m1 = m[1], m2 = m[2], m3 = m[3], iN = (N==0 ? 0 : 1/N);
	var Rj = [
		R[ 0] - m0*m0*iN,  R[ 1] - m0*m1*iN,  R[ 2] - m0*m2*iN,  R[ 3] - m0*m3*iN,  
		R[ 4] - m1*m0*iN,  R[ 5] - m1*m1*iN,  R[ 6] - m1*m2*iN,  R[ 7] - m1*m3*iN,
		R[ 8] - m2*m0*iN,  R[ 9] - m2*m1*iN,  R[10] - m2*m2*iN,  R[11] - m2*m3*iN,  
		R[12] - m3*m0*iN,  R[13] - m3*m1*iN,  R[14] - m3*m2*iN,  R[15] - m3*m3*iN 
	];
	
	var A = Rj, M = UPNG.M4;
	var b = [0.5,0.5,0.5,0.5], mi = 0, tmi = 0;
	
	if(N!=0)
	for(var i=0; i<10; i++) {
		b = M.multVec(A, b);  tmi = Math.sqrt(M.dot(b,b));  b = M.sml(1/tmi,  b);
		if(Math.abs(tmi-mi)<1e-9) break;  mi = tmi;
	}	
	//b = [0,0,1,0];  mi=N;
	var q = [m0*iN, m1*iN, m2*iN, m3*iN];
	var eMq255 = M.dot(M.sml(255,q),b);
	
	var ia = (q[3]<0.001) ? 0 : 1/q[3];
	
	return {  Cov:Rj, q:q, e:b, L:mi,  eMq255:eMq255, eMq : M.dot(b,q),
				rgba: (((Math.round(255*q[3])<<24) | (Math.round(255*q[2]*ia)<<16) |  (Math.round(255*q[1]*ia)<<8) | (Math.round(255*q[0]*ia)<<0))>>>0)  };
}
UPNG.M4 = {
	multVec : function(m,v) {
			return [
				m[ 0]*v[0] + m[ 1]*v[1] + m[ 2]*v[2] + m[ 3]*v[3],
				m[ 4]*v[0] + m[ 5]*v[1] + m[ 6]*v[2] + m[ 7]*v[3],
				m[ 8]*v[0] + m[ 9]*v[1] + m[10]*v[2] + m[11]*v[3],
				m[12]*v[0] + m[13]*v[1] + m[14]*v[2] + m[15]*v[3]
			];
	},
	dot : function(x,y) {  return  x[0]*y[0]+x[1]*y[1]+x[2]*y[2]+x[3]*y[3];  },
	sml : function(a,y) {  return [a*y[0],a*y[1],a*y[2],a*y[3]];  }
}

UPNG.encode.alphaMul = function(img, roundA) {
	var nimg = new Uint8Array(img.length), area = img.length>>2; 
	for(var i=0; i<area; i++) {
		var qi=i<<2, ia=img[qi+3];   
		if(roundA) ia = ((ia<128))?0:255;
		var a = ia*(1/255);
		nimg[qi+0] = img[qi+0]*a;  nimg[qi+1] = img[qi+1]*a;  nimg[qi+2] = img[qi+2]*a;  nimg[qi+3] = ia;
	}
	return nimg;
}

	
	
	
	
	


})(UPNG, pako);
})();

